Voltage sensitivity to power flows related to distributed generation

The recent development of dispersed generation leads to fact that distribution grids have to deal with the bidirectional power flow which may cause voltage rise above permissible level. Currently used voltage regulation scheme cannot completely and successfully cope with this problem. As a result of the further increasing penetration of distributed generation, the new voltage regulation system will have to be developed. Voltage in the nodes, i.e. voltage profiles, and voltage regulation capability are strongly dependent on impedance between buses, especially when indirect voltage regulating devices (using current injection) are deployed. The paper presents two variants of the medium voltage distribution grid as well as low voltage distribution grid which differ in length of power lines to simulate minimum and maximum impedance at the supply point, thus to determine marginal voltage sensitivities to distributed generation induced power flows. Voltage sensitivity, which is estimated by means of parametrical simulations, shows how much the voltage changes if active and reactive powers are injected, respectively. The results would be used for further development of voltage regulation strategy taking into account the regulation effectiveness, mainly in relation to the regulation provided by the distributed resources.